1. Field of the Invention
The present invention relates to a drive device for an optical disc apparatus for recording on or playing a CD, DVD, BD (Blu-ray Disc), or other optical disc.
2. Description of Related Art
Optical pickup feeding devices provided in drive devices for general optical disc apparatuses comprise a lead screw and a resin tooth that is advanced following the rotation of the lead screw while being in meshed engagement with the lead screw. The tooth is further attached to an optical pickup that can move along a guide shaft, is extended in a cantilevered state in a direction orthogonal to the axis line of the lead screw, and is provided with a tooth spring for elastically urging the tooth from a back part and urging meshing cogs thereof in the direction of meshing with the lead screw. Various improvements to the mechanisms of such optical disc apparatuses have also been proposed in recent years.
For example, there is disclosed in Japanese Laid-open Patent Publication No. 2009-140547 a configuration of a disc device comprising an optical pickup for scanning the recording surface of a disc, and a power transmission mechanism provided with a screw shaft and a moveable unit in the form of a resin molding that has meshing cogs in meshed engagement with the screw shaft, the moveable unit of the power transmission mechanism being joined to the optical pickup and constituting part of the optical pickup, and a guide shaft for defining the pathway of the optical pickup being attached to a frame; wherein a stop received by a catch on the frame to stop the uncontrolled movement of the optical pickup when the optical pickup starts to move uncontrollably is provided to a cantilevered spring piece extending from the moveable unit, and the optical pickup is provided with a spring cantilever that is brought up against the free end of the spring piece and caused to change the shape of the spring piece from a cantilevered shape to a double-end supported beam shape when the stop is received by the catch, and the spring piece is flexurally deformed.
For example, there is disclosed in Japanese Laid-open Patent Publication No. 2008-257826 a configuration of a feeding apparatus for an optical pickup comprising a lead screw and a resin toothed body that is advanced following the rotation of the lead screw while being in meshed engagement with the lead screw, the toothed body being attached to an optical pickup that can move along a guide axis adjusted at a slant, extended in a cantilevered state in a direction orthogonal to the axis line of the lead screw, and provided with a spring body for elastically urging the toothed body from a back part and urging meshing cogs thereof in a direction of meshing with the lead screw; wherein the position of urging the toothed body by the spring body in relation to the position of meshing between the meshing cogs of the toothed body and the lead screw is offset toward the free end of the toothed body and away from the meshing position.
Drive devices must be made thinner in order to respond to the recent demand for smaller optical disc apparatuses. Reducing the thickness of the traverse chassis on which the optical pickup is mounted is considered as a possible solution, but simply reducing the thickness results in insufficient strength. The size of the opening in the bottom surface of the traverse chassis must thus be reduced to enhance the strength.
Another feature is that the lead screw and the stepper motor are attached from the upper surface of the traverse chassis as the drive device is made progressively thinner. Accordingly, the shape of the section containing the meshing cogs of the tooth is also turned upside-down, and the section containing the meshing cogs must be fitted from the upper surface of the lead screw.
In the assembly operation, the tooth is attached from the bottom surface of the traverse chassis in a state in which the optical pickup is mounted. Time is required in this case for the fingers holding the tooth to come up against the traverse chassis and to attach the tooth to the chassis when the section containing the meshing cogs is run through to the lead screw and fitted to the lead screw from the section with a small opening in the bottom surface of the traverse chassis. Attaching the tooth is thus difficult to achieve in the assembly operation, causing problems in terms of reduced production efficiency.